What Is The Gut-Brain Axis & How Can It Affect Our Behavior?
It’s easy to assume that there is little connection between the brain and the gut. They’re entirely different parts of the body, after all! However, that assumption couldn’t be further from the truth. Take, for example, “gut feelings”, or those fluttery sensations you get in your stomach in certain situations. These are often signs that your gut is trying to communicate something that your brain hasn’t yet processed properly, and indicates that there is more to the gut and the brain than previously thought.
Recent research has taken it a step further and found that the health of the brain and the health of the gut are co-dependent, in the sense that the gut has an influence on how healthy your brain is vice versa. The system of communication that goes on between both the gut and the brain is now referred to as the gut-brain axis. But what is the gut-brain axis, exactly? And how might it affect our behavior?
What is the gut-brain axis?
In the simplest terms, the gut-brain axis is just what it sounds like: the line of communication between your gut and your brain. It is a little more complicated than just that, though. The communication that takes place between these parts of the body occurs between the central nervous system and the enteric nervous system. The central nervous system consists of the brain and spinal cord and controls most bodily and mental functions, whereas the enteric nervous system is a division of the peripheral nervous system that controls gut behavior without having to utilize the use of the central nervous system. It operates on its own.
The gut-brain axis also relies heavily on the vagus nerve, which has the ability to signal in regard to both sensory and motor function. It is the longest cranial nerve in the body and goes through the body from brain stem to colon. That signaling that occurs from the gut to the brain and vice versa is done along the vagus nerve.
What does the gut-brain axis do?
Recent research has found that the gut-brain axis and its communication system is important because of the way the microbiota in the gut influences the interactions between the two.
The part of the body that is used as a messenger of sorts is the neuron. The gut-brain axis relies on neurons in both the brain and the gut to send messages to each other using the vagus nerve. The gut-brain axis is also reliant on neurotransmitters. For example, neurotransmitters produced by cells in the gut, such as serotonin, can then be sent as signals to the brain.
Chemicals that affect the health of the brain are vital, and some of these are also created within the gut. Chemicals such as short-chain fatty acids are produced within the gut, and then used to affect how the brain functions.
Using the gut-brain axis, these chemicals and neurotransmitters are able to communicate effectively. The gut-brain axis is also connected through the immune system, which can plays a crucial role in the health of the mind and body.
Are gut health and mental health related?
The close bidirectional communication system between the gut and the brain suggests that mental health can be directly affected by gut health. Research has shown that gastrointestinal health issues can actually lead to mental illnesses. Some such GI disorders include dysbiosis and gut inflammation, both of which have been shown to cause depression and anxiety.
The microbiome – the collection of organisms that live in the gut and help to preserve health of the body as a whole – is especially important when it comes to mental health. Studies have shown that it’s so important that the use of probiotics, in an effort to restore healthy levels to a damaged microbiome, has been able to reduce the symptoms of mental health disorders.
As mentioned above, the gut-brain axis also has close ties with the immune system. The gut microbes that are in the body at all times can help to control the entry and exit of certain things, some of which can be harmful. If the gut microbes aren’t properly doing their job, it can elicit an immune response that goes on for too long, causing inflammation. Inflammation is linked to the development and onset of mental health disorders including depression.
How do gut bacteria affect overall mental and behavioral health?
The health of the gut also has a great influence on mental development and behaviour. Recent research has found that by acting directly on brain structure, the microbiota can change or alter a variety of things such as memory capacity, social behavior, and anxiety-like behavior.
Other research has also found that the state of someone’s gut health while they are a child can have a direct effect on their brain development. This means that the foods you once ate and the health of your stomach could have shaped the person you became later on in life.
Changes in the microbiome caused by stress have also been studied, and the results found that the brain and behavior can be changed following a change in the microbiome. This could be attributed to the inflammatory molecules produced in the gut known as inflammatory cytokines. These cytokines were shown to have a negative effect on brain neurochemistry, thus making people more likely to experience feelings of anxiety and depression.
The term you are what you eat has become more and more true as the research surrounding the gut-brain axis continues to build. It just goes to show that how you feed your body affects how you will feel in all aspects of health. By recognizing the importance of your gut microbiome and the gut-brain axis, you can begin to make the lifestyle changes needed to have healthy gut and a healthy mind.